# US 10,770,791 B2 · Systems and methods for reducing signal radiation in an unwanted direction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,791 B2 - Document ID: US10770791B2 - Status: Granted - Kind: B2 - Application number: 15/910,618 - Filed: 2018-03-02 - Published: 2019-09-05 - Granted: 2020-09-08 - Earliest claimed: 2018-03-02 - Assignees: PC-Tel, Inc. - Applicants: PC-TEL, Inc. - Inventors: Umesh Navsariwala; Jesse Lin - Web page: https://patentgrep.com/patent/US10770791B2 ## CPC - H01Q 3/36: with variable phase-shifters - H01Q 1/523: {between antennas of an array} - H01Q 3/2611: {Means for null steering; Adaptive interference nulling} - H01Q 3/28: varying the amplitude - H01Q 3/30: varying the {relative} phase {between the radiating elements of an array (H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence)} - H01Q 21/29: Combinations of different interacting antenna units for giving a desired directional characteristic (H01Q25/00 takes precedence) - H01Q 1/2291: {used in Bluetooth® or Wi-Fi® devices of Wireless Local Area Networks [WLAN] (H01Q1/241 takes precedence; WLAN in general H04W)} - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract An antenna system that can reduce signal radiation in an unwanted direction while preserving signal radiation outside of the unwanted direction is provided. The antenna system can include a signal input source with a main antenna and a secondary antenna each electrically coupled to the signal input source. The main antenna can transmit a primary signal to produce a primary radiation pattern in response to a first portion of energy from the signal input source, and the secondary antenna can transmit a secondary signal to produce a secondary radiation pattern in response to a second portion of energy from the signal input source. The secondary signal can be amplitude modified and phase shifted to position the secondary radiation pattern to cancel out or reduce a portion of the primary radiation pattern extending in an unwanted direction while substantially preserving portions of the primary radiation pattern outside of the unwanted direction. ## Claims ### Claim 1 An antenna system comprising: a signal input source; a main antenna electrically coupled to the signal input source; and a secondary antenna electrically coupled to the signal input source, wherein the secondary antenna is smaller in volume, footprint, or frequency bandwidth relative to the main antenna, wherein the main antenna transmits a primary signal to produce a primary radiation pattern in response to a first portion of energy from the signal input source, wherein the secondary antenna transmits a secondary signal to produce a secondary radiation pattern in response to a second portion of the energy from the signal input source, and wherein the secondary signal is amplitude modified and phase shifted to position the secondary radiation pattern to cancel out or reduce a first portion of the primary radiation pattern extending in an unwanted direction while substantially preserving a second portion of the primary radiation pattern outside of the unwanted direction. ### Claim 2 (depends on 1) The antenna system of claim 1 further comprising a continuous ground plane coupled to both the main antenna and the secondary antenna. ### Claim 3 (depends on 2) The antenna system of claim 2 wherein the ground plane includes a reflector portion separating the main antenna and the secondary antenna to assist in positioning the secondary radiation pattern. ### Claim 4 (depends on 1) The antenna system of claim 1 wherein the first portion of the primary radiation pattern includes a maximum point of the primary radiation pattern in the unwanted direction. ### Claim 5 (depends on 1) The antenna system of claim 1 wherein an amplitude of the secondary signal is based on a ratio of a first gain of the primary signal in the unwanted direction to a second gain of the secondary signal in the unwanted direction. ### Claim 6 (depends on 1) The antenna system of claim 1 wherein an amount of a phase shift of the secondary signal is equal to a difference between a first gain of the primary signal in the unwanted direction and a second gain of the secondary signal in the unwanted direction. ### Claim 7 (depends on 1) The antenna system of claim 1 wherein a power divider divides the energy from the signal input source between the main antenna and the secondary antenna. ### Claim 8 (depends on 7) The antenna system of claim 7 wherein the power divider unequally divides the energy from the signal input source between the main antenna and the secondary antenna such that the secondary signal has a lower amplitude than the primary signal. ### Claim 9 (depends on 1) The antenna system of claim 1 wherein the main antenna includes an array of antennas. ### Claim 10 (depends on 1) The antenna system of claim 1 wherein the unwanted direction is skyward. ### Claim 11 A method comprising: identifying a first maximum point of a primary radiation pattern extending in an unwanted direction, the primary radiation pattern produced by a main antenna transmitting a primary signal; positioning a second maximum point of a secondary radiation pattern to extend in the unwanted direction and align with the first maximum point of the primary radiation pattern extending in the unwanted direction, the secondary radiation pattern produced by a secondary antenna transmitting a secondary signal, and the secondary antenna being smaller in volume, footprint, or frequency bandwidth relative to the main antenna; and amplitude modifying and phase shifting the secondary signal to cancel out or reduce the first maximum point of the primary radiation pattern extending in the unwanted direction while substantially preserving portions of the primary radiation pattern outside of the unwanted direction. ### Claim 12 (depends on 11) The method of claim 11 further comprising coupling the main antenna and the secondary antenna to a continuous ground plane. ### Claim 13 (depends on 12) The method of claim 12 further comprising a reflector portion of the continuous ground plane separating the main antenna and the secondary antenna to assist in positioning the second maximum point of the secondary radiation pattern. ### Claim 14 (depends on 11) The method of claim 11 further comprising setting an amplitude of the secondary signal based on a ratio of a first vain of the primary signal in the unwanted direction to a second gain of the secondary signal in the unwanted direction. ### Claim 15 (depends on 11) The method of claim 11 wherein an amount of the phase shifting of the secondary signal is equal to a difference between a first gain of the primary signal in the unwanted direction and a second gain of the secondary signal in the unwanted direction. ### Claim 16 (depends on 11) The method of claim 11 further comprising a power divider dividing energy from a signal source between the main antenna and the secondary antenna. ### Claim 17 (depends on 16) The method of claim 16 further comprising the power divider unequally dividing the energy from the signal source between the main antenna and the secondary antenna such that the secondary signal has a lower amplitude than the primary signal. ### Claim 18 (depends on 11) The method of claim 11 wherein the main antenna includes an array of antennas. ### Claim 19 (depends on 11) The method of claim 11 wherein the unwanted direction is skyward. ### Claim 20 An antenna system comprising: a signal input source; a continuous ground plane; a main antenna array coupled to the continuous ground plane and electrically coupled to the signal input source; and a secondary antenna coupled to the continuous ground plane and electrically coupled to the signal input source, wherein the secondary antenna is smaller in volume, footprint, or frequency bandwidth relative to the main antenna, wherein the main antenna array transmits a primary signal to produce a primary radiation pattern in response to a first portion of energy from the signal input source, wherein the secondary antenna transmits a secondary signal to produce a secondary radiation pattern in response to a second portion of the energy from the signal input source, wherein the secondary signal is amplitude modified and phase shifted to position the secondary radiation pattern to cancel out or reduce a first portion of the primary radiation pattern extending in an unwanted direction while substantially preserving second portions of the primary radiation pattern outside of the unwanted direction, wherein a phase shift applied to one antenna in the main antenna array induces the second portions of the primary radiation pattern outside of the unwanted direction to tilt away from the unwanted direction, and wherein a reflector portion of the continuous ground plane separates the main antenna array and the secondary antenna to assist in positioning the secondary radiation pattern.